How to Charge an E-Bike for Maximum Battery Life
From safe charging to the longest possible lifespan, here’s everything you need to know about your electric bike’s power source.
If you bought a bike in the last couple years, chances are good it’s an e-bike. Electric bicycles are the fastest-growing type of bike in the U.S. today; in 2021 they surpassed road bikes as the third biggest category of bikes overall and in 2022 e-bike sales were over 800 million. E-bikes still outsell electric cars, and for good reason. The lightweight electric motor on an e-bike gives a powerful boost to all kinds of riding, especially utility cycling like commuting and errands. (Plus, there is a nice tax incentive for some e-bike riders.)
At the heart of that system is a powerful lithium-based battery. Taking proper care of that battery and knowing how to properly charge it is key to safely getting the best range and long-term battery life. Here’s what you need to know about charging your e-bike battery.
Safe charging basics
You should charge your battery inside, on the proper charger, and with the motor system powered off, says Kunal Kapoor, senior manager for quality and compliance at Bosch, a leading supplier of e-bike motor systems. While e-bike motors, batteries, and wiring are weather-resistant, “chargers aren’t intended for outdoor use,” he notes.
Using the proper charger is primarily a safety issue. With a modern lithium battery, Kapoor continues, when the battery signals it’s ready to accept a charge, “the battery monitoring system in the charger makes sure that the temperatures inside the battery are optimum to receive the charge,” and shuts off if needed. An off-brand charger—even rated to the same output—doesn’t have all the features of that battery management system, so current can flow to the battery even if temperatures rise, which is a fire risk.
The risk of battery fires is low, but Kapoor recommends people not leave batteries unattended while charging. You can leave the battery on the bike to charge or take it off, as long as it’s not sitting on or near flammable stuff (like the spare gas can in the garage, for example). If you’re looking at lower-priced e-bikes with house-brand or unbranded motor and battery systems, make sure the battery and charger carry a UL 2849 certification stamp from Underwriters Laboratories. This is the industry-wide standard for safe electric systems and battery charging for e-bikes. Some bike shops won’t work on e-bikes with motor and battery systems that lack this stamp, citing fire risk when left overnight in the store.
How to optimize battery range and lifespan
Let’s start with some definitions. Range is essentially runtime: how long a battery will last on a single charge, expressed in miles of riding. Range, even on the same bike, will vary; a flat commute to the office with just a light backpack will see better range than a fully loaded uphill ride home from Costco. Most e-bikes today get between 25-75 miles of range, depending on these factors.
Lifespan is how many times a battery can be discharged and recharged before it starts to lose significant capacity. When capacity starts to dip, you won’t notice less power while riding, but you will see range start to shrink. A common lifespan benchmark for e-bike batteries is 500 “full” discharge/re-charge cycles (if you use half the battery capacity and recharge, that’s half a cycle), which works out to about three to five years of normal use before capacity begins to drop noticeably.
Even though battery range and lifespan aren’t the same thing, they are linked, and actions that reduce range will also, over time, shorten lifespan. A big culprit, Kapoor says, is running the motor hard, like leaving it in Boost or Turbo mode all the time, which means a ride of a given distance relies progressively more on motor power than at lower assist levels. You’ll run the battery through charging cycles more quickly, which will shorten its life.
A less-obvious factor that strains motors and batteries is pedal cadence. Most e-bike motors are optimized for efficiency around a 70-90 rpm pedaling cadence. You can lower efficiency by pedaling too fast (Bosch motors, for instance, max out at 100-120 rpm depending on the system). common is sub-optimal efficiency from pedaling too slowly in a large gear. This is the same as “lugging the engine” in a car; whether gas or electric, the motor works harder. “Choose your gears wisely,” says Kapoor, to stay in that 70-90 rpm sweet spot.
Mistakes that kill your battery
When you buy a new e-bike, you should charge the battery to full before riding it because it’s likely been inactive for a while. But lithium batteries do not have “memory;” that is, they do not need to be fully discharged and fully recharged every time to hold their full capacity. In fact, it’s best if you don’t run a battery to zero, says Kapoor. “If you let the battery deplete completely, that may permanently damage it,” he says, and it will never recharge to its full original capacity.
If you’ll go a few weeks or more without riding the bike, store it (or at least the battery) in a dry, room-temperature space with the battery between 30-60 percent of full charge, says Kapoor. That’s the most stable level for long-term storage, and will lower the chance of a deep discharge that would damage your battery. Don’t leave your battery plugged in to the charger for long periods. It’s not necessary, and can create a short discharge/recharge cycle that will eventually reduce capacity. If you go long periods without riding the bike, check the battery charge monthly and partly recharge when it drops below 30 percent.
Lithium batteries are less affected by cold weather than other types of battery and you shouldn’t see reduced range while riding unless the temperatures are truly arctic. But researchers at the Department of Energy recently found storing lithium batteries below freezing for longer periods can damage part of the battery’s cathode, which will reduce its capacity. Lithium batteries also won’t charge effectively in cold temperatures. If you store your bike outside or in an unheated space and live in an area with sub-freezing temps, says Kapoor, bring the battery inside when not in use.
Also, keep your battery protected from extreme heat, like sitting next to a sunny window or a hot car. Excess heat can raise battery temperature enough to damage its components; in an extreme situation, it can contribute to what’s called thermal runaway, where a battery enters an unstable, uncontrollable self-heating state that can result in fire.
You don’t need to recharge after every ride. Topping off your battery sounds Smart, but over time it will reduce capacity more quickly. If you get 50 miles of range from a charge and ride 10 miles a day, you only need to recharge every three to four days.
When it’s time to replace
Even if you take great care of a battery, over time it will lose capacity. You’ll notice this on your bike’s range estimate on the controller unit. Capacity is a primary indicator of the health of a battery, so if you notice your range dropping to 70 percent or less of what it was when your bike was new, that’s a sign to start planning a replacement. If your battery is less than two years old and is well under original capacity, it might be a warranty claim (terms vary by manufacturer).
If it’s not a warranty issue, the decision on when to replace is personal preference, says Kapoor. “If you got 50 miles (of range) out of the battery originally and let’s say now you get 40, I wouldn’t classify it as ‘end of life’ if you can live with that 40-mile range,” he says. A battery with reduced capacity should still be safe, Kapoor adds.
Always purchase a name-brand replacement for your battery. Just as batteries and chargers should be paired, batteries and motors are designed to work together. And, says Kapoor, never try to repair a damaged battery or let someone else do it. Despite guides that claim you can, this is not just corporate greed or legal butt-covering by manufacturers. While e-bike batteries are almost always made from standard 18650 cells that are widely used in various products (even electric cars), those cells have a variety of different chemistries, capacities, and amperages, and that’s before we even get into connecting a string of them and repackaging the battery in the housing. The slightest mistake in any of that increases fire risk. If you need a new battery, just buy one.
Dealers that sell your brand of bike can order you a direct replacement for that bike or motor brand. Costs vary depending on battery size and brand, but plan on spending 400-800 for a new unit.
A dealer can also recycle your old one. A new program from Call 2 Recycle offers free e-bike battery recycling (paid for by bike and motor brands) through partner shops in almost every major city and many smaller ones. No participating dealers near you? Request an easy DIY shipping kit online.
Why recycle? Even a spent battery contains raw materials that can be re-made into fresh ones, at moderately less energy cost and less environmental damage than producing from virgin materials. Spent lithium batteries also have a fire risk in landfills and can leach toxic metals and other chemicals into the soil and air.
In case of fire
Though rare, battery fires do happen. If your battery gets hot to the touch while charging, unplug the charger from the wall immediately. If you can, put the battery in a metal container like a bucket (better yet, one filled with sand) away from anything flammable.
But if it’s not safe to handle, call 911 right away and tell the dispatcher that you have a lithium battery fire, which requires different firefighting methods than conventional fires. Don’t pour water on a battery fire; water and lithium react to produce hydrogen, which is highly flammable. A standard fire extinguisher may help, but in the event of a fire, special tools may be needed.
Review: Triangle Frame Battery Bag by Electric Rider
I’ve always been a fan of doing your own electric bicycle conversion instead of buying a retail ebike. By going the do-it-yourself (DIY) route, you have so much more freedom and room for customization, allowing you to choose from many different ebike parts.
Nearly every electric bicycle part has been designed to seamlessly integrate with standard bicycles to make the conversion process simple and easy. Throttles just slip over handlebar ends, motors mount easily in the wheel dropouts, and controllers can be bolted just about anywhere. The only problem can be fitting a battery onto a bicycle.
There are a few ebike batteries specifically built for mounting to bicycle frames, but generally DIY builders have been stuck building their own custom boxes and enclosures.
The best place to mount batteries on an ebike is in the center triangle of a bicycle frame. By mounting batteries in the triangle, you keep the weight centered in the bike and lower to the ground. But how can you securely mount your batteries in such an odd shaped area of the bike?
Enter: The Electric Rider Triangle Battery Bag!
Electric Rider Triangle Battery Bag
I got my hands on one of these new bags about 6 weeks ago and have been putting it through the paces ever since.
Now this isn’t my first triangle bag I’ve used for mounting batteries on an ebike. Readers of EbikeSchool.com might remember a review I did of the Ibera triangle bag, which I loved. Well, now I’ve found the Ibera bag’s big brother, and that’s the Electric Rider triangle bag.
This triangle bag has everything I loved about the Ibera bag, and a whole lot more!
Let’s start with the material. The exterior of the bag is made from what appears to be some type of tightly woven nylon, which gives the bag its water resistant feature. The zipper itself is a waterproof variety, just like I have on many of my hiking bags that are meant to keep all your gear dry in a downpour. The zipper closes behind a plastic-like sealing barrier which stops water ingress via the zipper. These two methods together make the bag highly water-resistant. I hesitate to say it is water proof, because I’m sure if you held a hose to it for long enough, especially around the wire ports, you’d start to get some water leakage. But fortunately for us, real rain isn’t directed like a sideways hose, and the light sprinkling rain I encountered left me with a bone dry interior. I haven’t had an heavy rains yet to give it a more intense test.
The wire ports themselves are really neat. One port in the front is covered by a nylon hood, which means the wires exit up but then immediately turn 90 degrees to the side. This helps to keep falling water from entering the exit port.
Many people will require a top mounted wire exit, especially if the controller is to be included in the bag, because that’s the most direct path to the handlebars and all of the devices you’ll have mounted there. This hooded exit port is a great way to provide a top mounted exit port without the risk of water easily getting through.
The second wire port is located on the underside of the bag and is similar to the headphone ports on many backpacks. A spiral cut piece of rubber holds the port closed and tightly seals around wires that exit the port. These two different designs for top and bottom mounted wire ports should provide many options for accessing your battery and any other electronics stored in the bag.
This might be a good chance to check back in on the Ibera triangle bag I used before I got the Electric Rider triangle bag. While it was nice and roomy, it didn’t have any wire ports, probably because it was never meant for use on electric bicycles. That’s one of the biggest advantages of the Electric Rider triangle bag: it’s designed specifically for ebike use.
A great example of how this triangle bag is meant for ebikes is that included padding. The bag itself doesn’t feature built in padding, rather there is a long strip of foam padding included with the bag to allow the user to shape it to whatever battery they are using. At first I wasn’t a fan of this method, as I would have preferred a bag that came padded on all sides. But as I started using the bag, I realized how useful this feature was. By not padding the entirety of the bag, Electric Rider left as much usable space as possible in the bag. I could then add their padding only where I needed it. This meant the bag could remain as wide as possible for holding as thick a battery as you can get in there. Then you can just wrap the padding around the corners or bottom of the battery (or top of the battery if you want to put more stuff in there on top of it) as you see fit.
One downside of the triangle bag is that there isn’t a great way to protect against theft. This is a problem inherent in all battery bags, since they don’t lock to the bike the way an aluminum case battery can. One trick to get around this is to use a luggage lock on the two zipper pulls. This isn’t going to stop a determined thief, but it will prevent opportunistic crime where a would-be thief sees and easy target and goes rummaging through your battery bag. Check out my article on Ebike theft prevention to learn more here.
Adding a lock to the zippers is something you very well may want to consider, especially when you see how much expensive lithium you can cram into this bag. In terms of size, I’m not sure how else to say it other than that this bag is cavernous. It just keeps going. It will fill up the triangle on most bikes (and might even be too big for some, though it will squish down to fit) and its width means you can stuff a lot of battery into it.
The EM3EV triangle bag (which is a nice bag in its own right, and one which I will be reviewing here soon too) has been the largest triangle bag to date. Well, now we’ve got a new king in town, as the Electric Rider triangle bag is even bigger.
To test it out, I put it in the biggest, weirdest and most open frame I could find: the Electra Townie. This gigantic frame can fit enough lithium to take you half way across the country. The only problem is fitting it in there somehow. But the Electric Rider triangle bag actually surprised me by fitting in this gigantic frame triangle (or perhaps ‘abstract quadrilateral’ is more accurate than ‘triangle’). You can see that the frame is so large on this bike that the bag stretches a bit to fit. However, the long mounting straps that Electric Rider designed into the bag means that it can hold on securely even with the edges of the bag an inch or more from the frame members.
There is even still plenty of room for another bag up front to hold a controller, keys, wallet, sunglasses etc. The large shape of the bag and the extra long straps make this bag adaptable to many different size and shapes of bicycle frames. It even fit nicely in another weird yet smaller frame I had: a fat bike.
But fitting in a frame is just part of the story. A battery bag has to hold a lot of battery if it wants to live up to its name. So the next test involved loading the bag up with a bunch of batteries to see how well it worked.
For comparison, I tried loading in a few 48V 10AH lithium packs that I had on hand. Just for reference, my Ibera triangle bag could only hold one pack, and it had trouble closing. I was able to fit two of the 48V 10AH batteries into an EM3EV triangle bag, but the zipper wouldn’t close. Those same two packs fit in the Electric Rider triangle bag easily, and the bag was able to close with plenty of room for a controller and some other goodies.
I could even get three packs in the Electric Rider bag, but then I had trouble closing it.
Not for lack of trying though. A bit like battery Tetris.
An ebike bag that can carry 48V 20AH isn’t bad at all – that’s about twice as much battery as most retail ebikes feature. And remember, each of those packs I used had their own Battery Management System (BMS), wiring and connectors, not to mention cell arrangement designed for a single pack. If that had been one pack instead of three, and without all the redundant components, I think 48V30AH would have fit in the Electric Rider bag easily. It certainly swallowed my big 72V battery without a problem.
But all that space for batteries means the bag is going to get pretty heavy. Electric Rider was prepared for that though, and included nine (yes, nine!) wide velcro straps for holding the bag into the frame triangle. That sucker isn’t going anywhere.
So what does a bag like this cost? Well that’s the kicker – you’re going to have to shell out 65 to put one on your bike. Compared to the Ibera bag, that’s about 4 times the price, which might be hard to swallow for your first conversion. But when it comes to fitting the maximum amount of battery in your triangle, there aren’t many options out there that can do it besides Electric Rider’s triangle bag. And that’s when the price suddenly makes it seem so worth it. If you’re stuffing 20 AH or more of lithium in your bike’s frame triangle, you’re probably talking about a battery that is nearing 1,000 as it is. At that point, it just makes sense to protect that investment with a quality bag like this.
Want to get your own triangle bag? Head on over to Electric Rider’s website to check out their bag here.
Micah is a mechanical engineer, tinkerer and husband. He’s spent the better part of a decade working in the electric bicycle industry, and is the author of The Ultimate DIY Ebike Guide. Micah can usually be found riding his electric bicycles around Florida, Tel Aviv, and anywhere else his ebikes wind up.
Комментарии и мнения владельцев
They are about to release a new bag with more wire out locations and even a few with no logo. I now have 4 bags from 4 makers. The one is simply the best. And now with the wire out port at the lower corner for a mid drive, my near perfect bag. Get in line i preordered the unlabeled. but won’t give up the logo version. Now if someone would copy the Lunacycle zip tie version with a bag of this quality I d be near nirvana.
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My favorite source for batteries right now is Battery Hookup. They’ve also generously offered all of my readers a 5% discount if you use the discount code EBIKE.
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All the help and knowledge I’ve provided here on EbikeSchool.com is 100% free If you want to support this site and help me keep it free, consider checking out my ebook and video course on building ebikes.
Ebikeschool.com has a lot of great info, but I’ve spent countless hours putting even more info, examples, how to’s, reviews, maintenance steps and buying guides into my book and video course. They are some of the most fact-dense and info-rich ebike resources available today. So check them out to see if they can help you with your own ebike!
If you want to learn more in-depth about building your own lithium battery, you’ll want to check out my book “DIY Lithium Batteries: How To Build Your Own Battery Packs” which is an Amazon #1 Bestseller in multiple categories! You can get it here on Amazon.
And if you don’t want to purchase my book (or you already have a lot of ebike knowledge), you can still support this site by simply clicking on this link before you shop on Aliexpress. Basically, that’s an affiliate link that shows Aliexpress that you came to them via my site. It doesn’t effect you at all, but if you make a purchase, this site will get a small percentage of the profit that Aliexpress makes. It’s a simple way to help support this site so I can pay the hosting and keep providing more free info (and to keep this site free of annoying ads). I have some of those affiliate links on a limited number of articles on my site. When I personally buy and test products that I find to be a combination of great quality and great prices, like these batteries, for example, I like to share them through those affiliate links. Again, it costs you nothing, but it allows me to keep cranking out more info and content for you guys!
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Triangle Ebike Battery 48v 52v 28.8Ah 21700 LG Li-ion Cell Battery Pack for Electric Bicycle
This triangle shape E-bike battery is suitable for 0-1800W eBike motor.
Built-in Famous Brand LG4800 Lithium Cell. With on/off button to help you save power.
Lighted battery LED power Indicator, inform you to charge battery in time.
Each pack have ran through a full charge and discharge test in produce, to make sure you are getting every amp hour you paid for.
The E-bike battery charge cycle exceeds 1000 times, life expectancy of up to 5 years.
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Hard plastic triangle case, the case is stronger a lot than normal cloth triangle bag, to better protect the cells. Using 21700 batteries, it has a larger capacity, while fewer batteries have a larger capacity. With on/off button,upgrade metal switch,safer and more convenient. Power display accurate display of battery level,inform you battery power in anytime. Superior quality reclosable fastener with strong tear resistance.Easy installation and removal. The charging port of cannon head can charge more quickly. Support 3-5A fast charging. The battery support larger capacity, get longer riding distance.
48V 28.8Ah BMS 50A LG4800 for 0-1 5 00W Related Voltage: 48V Capacity: 28.8Ah Built-in BMS: 50Amp Applicable Power: 350w-1500w Charging Time: 7-8 hours Size: 36423239481mm Discharge Connector: A piece of XT60 Connector
52V 28.8Ah BMS 50ALG4800 for 0-1 8 00W Related Voltage: 52V Capacity: 28.8Ah Built-in BMS: 50Amp Applicable Power: 350w-1800w Charging Time: 7-8 hours Size: 36423239481mm Discharge Connector: A piece of XT60 Connector
【 LED Display 】
Accurate display of battery level-The LED display pannel on this battery show the battery level in real time. Lighted LED power Indicator, informing you to charge your battery on time. Press the button to display power and voltage values. With on/off button to help you save more power.
【 Built-in Genuine A Grade Lithium-ion Cell 】
This triangle battery pack is made of LG brand lithium-ion cell. Good quality brand cell ensure it’s long lifespan for usage. Each pack have ran through a full charge and discharge test in produce process, to make sure you are getting every amp hour you paid for.
【One month free Return/ One Year Warranty/ Lifetime Technical Support】
One month free return, one year quality assurance, if your product damaged within one year, we offer free repair service in USA, if the battery can’t repaired, we will send new one to you for free. Any problem, please contact seller for help.
1pcs Triangle battery 1pcs AC adapter 1pcs Power cable 1pcs Discharge plug 10pcs Battery’s straps 1pcs User manual
Select a suitable parameter for your ebike convertion kit. If you prefer other discharge connector, such as XT90, T Plug, please contact seller after order.
If there is no voltage and capacity that you want to buy, contact the seller for price quote. We can do custom build for you.